A common collector amplifier uses a transistor whose h-paramters

Home » Physical Electronics Devices and ICs » Physical electronics devices and ics miscellaneous » Question

A common collector amplifier uses a transistor whose h-paramters are h_ic = 900 Ω, h_fc = 25 and h_rc = 1. If source and load resistances are 10 K and 500 Ω respectively, the voltage gain of the amplifier is—

1. 0·53
2. 0·93
3. 1·2
4. 2·3

Correct Option: A

Given, h_ic = 900 Ω, h_fc = 25, h_rc = 1, Rs = 10 kΩ = 10,000 Ω, R_L = 500 Ω
We know that voltage gain for common collector configuration is given by expression

A_v =		V₀	=	R_L
		V_s		R_s / (β + 1) + R_L + Y_e

or A_v =		500	=	R_L	(neglecting re since r_e =		V_I	=	25 mV	and β = h_fc = 25)
		V_s		10‚000 / (25 + 1) + 500			I_E		I_E

or A_v ≈ 0·53
Hence alternative (A) is the correct choice.